Experimental cryptococcal-induced myocarditis

Rabbits and Wistar rats developed myocarditis after intracardiac inoculation with Cryptococcus neoformans. Myocardial lesions were observed on the 1st, 2nd, 3rd and 4th weeks after this inoculation in all animals. The cardiac lesions consisted of focal necrosis with mononuclear inflammatory cells infiltration in the myocardium. Cryptococcus neoformans itself was found by PAS stain and indirect immunofluorescence stain by the 2nd week after the inoculation. Maximal cardiac lesions were observed in the 2nd week and thereafter, the lesions showed progressive scarring. In the 9th week, there were fibrotic lesions and we were not able to demonstrate cryptococcal antigens in these lesions. Fungemia and antibody for Cryptococcus neoformans were not found over the entire period. Cryptococcal meningeal lesions were observed in all animals. In the animals given an intracardiac administration of saline. Pseudomonas aeruginosa, and Serratia marcescens, there were no myocardial lesions. The relationship of this experimental fungal myocarditis and fungal endocarditis in human is discussed.